Process for the production of nonlaterally reversed positive copies by heat development



can be obtained by producing sulphur dyestuffs.

United States Patent O PROCESS FOR THE PRODUCTION OF NON- LATERALLY REVERSED POSITIVE COPIES BY HEAT DEVELOPMENT Hildegard Haydn and Anita von Kiinig, Leverkusen, Germany, assignors to Agfa Aktiengesellschaft production of non-laterally reversed positive copies and more especially to a process in which a silver halide layer is developed with a silver halide developing substance and in which the developer substance contained in the unexposed areas of the silver halide layer is transferred to a second layer, which is brought in contact with the first layer and which contains one or more substances which are insensitive to light and which produce colored compounds with the said developer substances preferably at elevated temperatures.

It has been found that the image in the transfer layer forming the sulphur dyestuffs, it is possible to employ all processes which are known for this purpose and which operate at temperatures such as those usually employed in the heat development. The color shades of the result- .ing images vary according to the developer substance which is used. The depth of color and tone of the dyestuffs can be influenced by adding heavy metal salts, such as copper sulphate, zince sulphate, ferric nitrate, alum, cerium nitrate, uranium nitrate, Reinecke salt and others or amines, such as aromatic monoand polyamines, which may be substituted as for instance aniline, toluidine, xylidine, m-phenylendiamine, m-toluylendiamine, asym. dimethyl-pphenylendiamine, 4,4'-diaminoride, silver bromide and silver iodide emulsions, even.

admixed as desired with one another, of high or low sensitivity, with any desired gradations and also with normal, high or low silver content. Added to these negative emulsion layers to serve as developer substances are aromatic amino or hydroxy compounds or aminohydroxy compounds, and also amino or hydroxy compounds or aminohydroxy compounds of diphenylamines, and diphenyls.

The transfer layer contains compounds which easily split off sulfur at temperatures of about 80l50 C., such as ammoniumsulfide, metal sulfides as for instance alkali and alkaline earth sulfides (sodiumsulfide, calciumsulfide), ironsulfide, zincsulfide, cadmiumsulfide, aluminiumsulfide (that is to say such metal sulfides are of special advantage which are soluble in mineral acids, such as 10% hydrochloric acid), ammoniumpolysulfides, sodiumpolysulfides, calciurnpolysulfides (Na S Na S- CaS C387) or other alkali or alkaline earth polysulfides, polythionates, such as sodium trithionate, bariumtrithionates, Wackenroders solution and salts derived from said solution, such as potassium tetrathionate and pentathionate, and furthermore organic compounds such as thioamides, especially thiourea, thiobenzamide, and thioacetamide. In order to accelerate the decomposition there may be For added basic or acid substances to the layer. The sulfur "ice compounds are preferably applied in quantities amounting to about 15 and 50 g. per litre of solution of binding agent for the transfer layer.

As a binding agent for the transfer layer and for the silver halide layer there may be used gelatine, polyvinylalcohol, polyvinylpyrrolidone, celluose derivatives, alginates, mixtures of said substances or other natural-or synthetic film forming substances which are swellable' in water. To the solutions which are used for the prepa-' ration of the transfer layers there are added with ad-' vantage compounds which are capable of forming water containing crystals, such as sodiumacetate, trisodiumphosphate, sodiumsulfate. In this case the solutions must contain sufficient water so that after evaporation the transfer layer contains a certain quantity of crystal water. The compounds may also be added to the silver halide emulsion layer. Instead of or together with the above compounds there may be added glycerine, glycols or corresponding hygroscopic substances to the transfer layer and/or to the silver halide emulsion layer. Thequantities of said compounds may vary within wide limits according to the nature of the substances actually used.. Sodium acetate may for instance be used in quantities of about 5-150 g. per litre of silver halide emulsion or solution for the preparation of the transfer layer. The glycerine and the other compounds may be applied in corresponding quantities. i

The heavy metal salts are preferably applied in quantitles of about 520% by weight as calculated on the sulfur compounds. The developing substance is added to the silver halide layer preferably in quantities of about 8-20 g. per litre of silver halide emulsion. The pH of the emulsion is preferably kept between 5.0 and 6.5.

For certain purposes, it can be advantageous for the transfer paper to be coated on both sides, it being possible for the positive paper to be arranged between two negative papers during the heat development, so that a double-sided copy is obtained in a single operation.

For carrying out the process the silver halide layer is exposed to an object to be reproduced and thereafter brought in contact with the transfer layer. The combined layers are then heated for about 10-60 seconds to a temperature of about l50 0, preferably 110- 135 C., whereby the transfer layer may be heated to a somewhat lower temperature than the negative layer, such as ll0 C. Hot presses, high-glaze presses which can be heated electrically, drying drums and the like are suitable for the development and simultaneous image transfer. After separating the two layers a laterally correct color reproduction of the original to be reproduced is obtained.

EXAMPLE 1 Negative material 10 g. of the hydrochloric acid salt of 4-aminophenol, g. of sodium acetate and 150 cc. of water are added to 1 litre of any desired silver halide emulsion. Other additives known in the emulsion art can be used. The emulsion is cast on to paper or any other conventional support and dried.

Positive (Transfer) material '20 g. of sodium sulphide are dissolved in 500 cc. of water and made up with a 10% aqueous solution of polyvinyl alcohol to 1000 cc. The solution is cast on to paper or any other suitable layer support and dried.

After exposure, the negative paper is brought into contact with the positive paper. The two papers are then subjected for 10 to 60 seconds to a temperature of to by means of a glazing press or two flat-irons. The positive paper can be heated to a lower temperature.

3 A reddish-brown image is obtained in the positive layer when the two layers are separated.

Negative material Positive material '20 g. of sodium. trithionate, 10 g. of sodium acetate andZ g. of Reineckesalt are dissolved in 600 cc. of

Water, and 300 cc. of a 10% aqueous solution of polyvinyl alcohol and 100 cc. of glycerine are added thereto. The solution is cast on to a suitable support and dried.

The processing takes place as indicated in Example 1 and a positive image of brown to brownish-violet color is obtained.

EXAMPLE 3 Negative material 10 g. of p-methylaminophenol sulphate and 100 g. of sodium acetate dissolved in water are added to 1000 cc. of a silver halide emulsion. Other additives can be used. A silver halide layer is cast from said emulsion on a paper support.

Positive material 40 g. of sodium trithionate are dissolved in 600 cc. of water and 300 cc. of a 10% aqueous solution of polyvinyl alcohol and 100 cc. of glycerine are added thereto.

After proceeding as described in Example 1, a light brown image is obtained.

EXAMPLE 4 Negative material 10 g. of 5-amino-2-cresol are dissolved in Water and added to 1000 cc. of a silver halide emulsion, to Which r The additives referred to in Example 1 can be used for the negative material. a e

are then added 200 g. of sodium acetate. This emulsion is coated on a paper support and dried.

Positive material As described in Example 1, 2 or 3. The positive obtained after processing as described in Example 1' is light brown in color.

EXAMPLE 6 Negative material '10 g. of 3-chloro-4-aminophenol are added to 1000 cc. of a silver halide emulsion. 100 g. of sodium acetate dissolved in a little water are added thereto. This emulsion is cast ona paper support and dried.

Positive material As in Example 1, 2 or 3.

A greyish brown image-is obtained after processing as in Example '1.

EXAMPLE 7 Negative material 10 g. of 2,5'-toluylene 'diamine are dissolved in water glycerine are added.

and added to 1000 cc. of a silver halide emulsion. 150 g. of sodium acetate, 10 cc; of 40% citric acid and 20 cc. of 5% benztriazole are added thereto. This emulsion is cast on a paper support and dried.

Positive material 7 As described in Examples l, 2 and 3. A red dyestufi image is obtained after processing as described in Example 1.

EXAMPLE 8 Negative material 10 g. of 2.5-diaminoanisole are dissolved in water and added to 1000 cc. of a silver halide emulsion, to which are then added cc. of sodium acetate and 20 g. of benztriazole. This emulsion is cast on a paper support and dried.

Positive material As in Example 1, 2 or 3. A bright red image dyestuff is obtained after the processing as described in Example 1.

EXAMPLE 9 Negative material 10 g. of 4-4-diaminodiphenylamine hydrochloride are dissolved in water and added to 1000 cc. of any desired silver halide emulsion. 100 g. of sodium acetate, 10 cc. of 40% citric acid and 20 cc. of 5% benztriazole are then added to the emulsion. This emulsion is coated on a paper support and dried.

Positive material As in Example 1, 2 or 3. A bluish-violet dyestufi image is essing as in Example 1.

EXAMPLE 10 Negative material produced after proc- As described in Example 3.

Positive material A solution is prepared containing 40 g. of sodium trithionate, 5 g. of 1,3-phenylene diamine, 1 g. of ferric chloride, 600 cc. of polyvinyl alcohol and 100 cc. of glycerine. This solution is coated on a paper support and dried.

After processing as described in Example 1, a violet dyestufi image is obtained.

EXAMPLE '11 Negative material 8 g. of pyrocatechol dissolved in water, 200 g. of hydrated sodium acetate crystals and 15 cc. of benztriazole (5%) or other stabilizers are added to one liter of silver halide emulsion. This emulsion is cast on a paper support and dried.

" Positive material 30 g. of thiourea are dissolved in water and added to 500 cc. of an aqueous polyvinyl alcohol solution (10%). Thereupon 10 g. of sodium carbonate and 100 cc. of

After processing as in Example 1 a laterally non-reversed dyestufi' image'of the original is obtained.

EXAMPLE 12 Negative material 10 g. of 3-hydroxy-4-aminidiphenylamine hydrochloride are dissolved in Water and added to 1000 'cc. of a silver halide emulsion. g. of sodium acetate and 15 cc. of benzotriazol (5%) or the equivalent amount of an- .other stabilizer are added to the emulsion. This emule sion is cast-on a paper support and dried.

Positive material A solution of 15 g. of thioacetamide, 1 g. of copper sulfate and 100 cc. of glycerine are added to 700 cc. of polyvinyl alcohol.

After proceeding as described in Example 1 a dark colored positive image is obtained.

What we claim is:

1. Process for the production of non-laterally reversed photographic sulfur-dyestufi images without the use of treating baths, said process being characterized by the steps of providing a light-sensitive solid silver halide emulsion layer that contains an organic silver halide developer selected from the class consisting of aromatic amino and aromatic hydroxy developers which forms a sulfur-dyestuif when heated to from 80 to 150 C. with a compound splitting 01f sulfur, providing a separating supported transfer layer containing a compound which splits oif sulfur at a temperature of about 80 to 150 C., at least one of said layers containing hydrated material that liberates suflicient moisture on heating to 80 to 150 C. to facilitate transfer between the layers, photographically exposing the emulsion layer, contacting the exposed emulsion layer with the transfer layer, and subiecting said combined layers to a heat treatment at a temperature of about 80 to 150 C., to cause only said organic developer to transfer from the unexposed places of said silver halide layer into said transfer layer and react in the transfer layer to form a positive sulfur-dyestufi image of the original to which the silver halide layer was exposed, and thereafter separating said two layers.

2. Process according to claim 1, wherein the hydrated material is a hydroscopic substance.

3. Process according to claim 1, wherein the hydrated material has molecules of water of crystallization therein.

4. Process according to claim 1, wherein the transfer layer contains a heavy metal'salt that changes the color of the sulfur-dyestutf image.

5. Process according to claim 1 wherein the heat treatment takes place at a temperature of between about and C. and is maintained for a period of between about 10 and 60 seconds.

6. Process according to claim 1 wherein the pH of the silver halide emulsion layer is about 5 to 6.5.

7. Process according to claim 1 wherein said silver halide developer is present in the silver halide emulsion in an amount corresponding to 8 to 20 g. per liter of that emulsion.

8. Process according to claim 1 wherein the transfer layer contains an amine selected from the class consisting of aniline, toluidine, xylidine, m-phenylenediamine, mtoluylendiamine, asym. dimethyl-p-pheny1endiamine, 4,4- diaminodiphenyl, 3,3-dimethoxy-4,4' diaminodiphenyl, 1,4-naphthylendiaminesulfat, 2,6-naphthylen-diamine.

References Cited in the file of this patent UNITED STATES PATENTS 742,405 Eichengrun et a1 Oct. 27, 1903 809,651 Vathis Ian. 9, 1906 2,352,014 Rott June 20, 1944 2,704,721 Land Mar. 22, 1955 2,740,717 Yutzy et a1. Apr. 3, 1956 2,747,999 Yutzy et a1. May 29, 1956 FOREIGN PATENTS 22,580 Great Britain Sept. 13, 1906 427,962 Great Britain Apr. 29, 1935 OTHER REFERENCES Photographische Korrespondenz, 87 Band, p. 29,

' #34 (August 1951 J. Phot. Science, v. 2, January-February 1954, p. 10.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,971,840 February 14, 1961 flil degard Haydn et 31 It is hereby certified that. error appears in the above numbered patnt requiring correction and that the said Letters Patent. should read as orrec'bed below.

i Column 4, line 26, for "4-4-01iaminodiphenylamine" {read 4,4 diaminodiphenylamine Signed and sealed this 3rd day of October 1961.

SEAL) Ltest:

RNEST W. WIDER DAVID L. LADD ttesting Officer Commissioner of Patents USCOMM-DC 

1. PROCESS FOR THE PRODUCTION OF NON-LATERALLY REVERSED PHOTOGRAPHIC SULFUR-DYESTUFF IMAGES WITHOUT THE USE OF TREATING BATHS, SAID PROCESS BEING CHARACTERIZED BY THE STEPS OF PROVIDING A LIGHT-SENSITIVE SOLID SILVER HALIDE EMULSION LAYER THAT CONTAINS AN ORGANIC SILVER HALIDE DEVELOPER SELECTED FROM THE CLASS CONSISTING OF AROMATIC AMINO AND AROMATIC HYDROXY DEVELOPERS WHICH FORMS A SULFUR-DYESTUFF WHEN HEATED TO FROM 80 TO 150*C. WITH A COMPOUND SPLITTING OFF SULFUR, PROVIDING A SEPARATING SUPPORTED TRANSFER LAYER CONTAINING A COMPOUND WHICH SPLITS OFF SULFUR AT A TEMPERATURE OF ABOUT 80 TO 150*C., AT LEAST ONE OF SAID LAYERS CONTAINING HYDRATED MATERIAL THAT LIBERATES SUFFICIENT MOISTURE ON HEATING TO 80 TO 150*C. TO FACILITATE TRANSFER BETWEEN THE LAYERS, PHOTOGRAPHICALLY EXPOSING THE EMULSION LAYER, CONTACTING THE EXPOSED EMULSION LAYER WITH THE TRANSFER LAYER, AND SUBJECTING SAID COMBINED LAYERS TO A HEAT TREATMENT AT A TEMPERATURE OF ABOUT 80 TO 150*C., TO CAUSE ONLY SAID ORGANIC DEVELOPER TO TRANSFER FROM THE UNEXPOSED PLACES OF SAID SILVER HALIDE LAYER INTO SAID TRANSFER LAYER AND REACT IN THE TRANSFER LAYER TO FORM A POSITIVE SULFUR-DYESTUFF IMAGE OF THE ORIGINAL TO WHICH THE SILVER HALIDE LAYER WAS EXPOSED, AND THEREAFTER SEPARATING SAID TWO LAYERS. 